Fix PySide6 enum access for Windows compatibility

- Import QStyle from PySide6.QtWidgets
- Use QStyle.StandardPixmap.SP_ComputerIcon instead of self.style().SP_ComputerIcon
- Use QSystemTrayIcon.ActivationReason.DoubleClick instead of QSystemTrayIcon.DoubleClick

PySide6 requires fully qualified enum paths unlike PyQt5.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

gui/main_window.py

@@ -9,7 +9,7 @@ from PySide6.QtWidgets import (
     QMainWindow, QWidget, QVBoxLayout, QHBoxLayout,
     QLabel, QPushButton, QTabWidget, QGridLayout,
     QScrollArea, QFrame, QMenu, QMenuBar, QStatusBar,
-    QMessageBox, QApplication, QSystemTrayIcon
+    QMessageBox, QApplication, QSystemTrayIcon, QStyle
 )
 from PySide6.QtCore import Qt, Signal, QTimer, QSize
 from PySide6.QtGui import QIcon, QPixmap, QAction, QFont
@@ -299,7 +299,7 @@ class MainWindow(QMainWindow):
             self.tray_icon.setIcon(QIcon(icon_path))
             self.setWindowIcon(QIcon(icon_path))
         else:
-            self.tray_icon.setIcon(self.style().standardIcon(self.style().SP_ComputerIcon))
+            self.tray_icon.setIcon(self.style().standardIcon(QStyle.StandardPixmap.SP_ComputerIcon))
 
         # Tray menu
         tray_menu = QMenu()
@@ -314,7 +314,7 @@ class MainWindow(QMainWindow):
 
     def on_tray_activated(self, reason):
         """Handle tray icon activation."""
-        if reason == QSystemTrayIcon.DoubleClick:
+        if reason == QSystemTrayIcon.ActivationReason.DoubleClick:
             self.show()
             self.activateWindow()